Tether clamp and implantation system

ABSTRACT

A clamp housing assembly and method for providing stabilization as a bone anchor during an operation. The assembly includes a housing, a locking element and a band. The housing defines a longitudinal axis, a center recess, and at least one slot. The housing has two opposing arms extending from a base. At least a portion of the inside surface of each arm may be threaded and at least a portion of the outside surface of each arm may be planar. The locking element is positionable within the recess in a co-axial relationship to the housing. The band is sized for travel along a predetermined path defined in part by the at least one slot in the housing.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/534,453, entitled TETHER CLAMP AND IMPLANTATIONSYSTEM and filed Sep. 14, 2011, and U.S. Provisional Patent ApplicationSer. No. 61/595,296, entitled TETHER CLAMP AND IMPLANTATION SYSTEM andfiled Feb. 6, 2012, the entire disclosure of each is incorporated hereinby reference, to the extent that either is not conflicting with thepresent application.

BACKGROUND

The human skeleton is formed of bones, each bone performing a structuralrole, either individually or collectively with other bones. For example,the spine is made up of approximately 24 vertebrae, each composed ofseveral portions, which act as a whole to surround and protect thespinal cord and nerves, provide structure to the body and enable fluidbody motion in many planes. The vertebrae are normally aligned along anaxis, with each vertebra presenting a posterior wall from which projectsa spinous process and two side edges having walls from which project theribs and/or transverse processes.

An individual's spine may be damaged or otherwise compromised in one ofmany ways. A spine may present an abnormal curvature, such as forexample, vertebrae inclined and rotated relative to one another andrelative to the vertebral axis. In such a curvature, the lateral edgesof the vertebrae situated on one side are closer to one another and forma concave curve, while the lateral edges on the other side are spacedapart from one another and form a convex curve. This condition canresult in subsequent and serious conditions, such as for example,abnormalities of the cardiac, pulmonary, neuromuscular andgastrointestinal systems.

An individual's spine may also be damaged by one or more fracturedvertebrae. Spine osteosynthesis, the reduction (bringing together) andfixation of a bone fracture with implantable devices, is a knowntreatment of a spinal fracture. Specifically, osteosynthesis is asurgical procedure with an open or percutaneous approach to thefractured bone, which aims to bring the fractured bone ends together andimmobilize the fracture site while healing takes place.

To correct these and other conditions, conventional procedures have beendeveloped using mechanical implants to straighten or otherwise holdsuccessive vertebrae in a fixed position. To keep the vertebrae in thedesired relative position, hardware, such as a screw, is inserted intothe vertebrae. The screws include tulip heads and act as an anchoringpoint for a connecting member between vertebrae, such as a straightsurgical rod.

The use of screws introduces risk into the surgical procedure and maycause additional damage to the vertebrae. Spinal clamps have beendeveloped that provide additional anchor points along the spine when theuse of a screw is not possible or not optimal. Known exemplary spinalclamps introduce further risk and complexity into the surgery, includinginstallation complexity, inadequate size offerings and additional parts.

Similar risk and complexity exist in orthopedic surgery in other areasof the body adjacent or remote from the spine.

SUMMARY

The present application describes various exemplary methods andapparatus for a spinal clamp, specifically, a tether clamp installationsystem.

In an embodiment, a spinal clamp assembly includes a clamp housing, alocking element, and a band. The clamp housing may be a one piece base,have no moving parts, and defines at least one slot for passage of theband. The housing is adapted to receive a surgical rod without the useof a retaining clip or other hardware beyond the locking element. Thelocking element may be positioned co-axial with the housing. Duringinstallation, the band is tightened around a vertebra and tensioned intoa tightened position by a tensioning instrument.

In another embodiment, a spinal clamp system includes a spinal clampassembly, locking and tensioning tools, and a tensioning instrument. Thetensioning instrument has a distal end which engages the spinal clampassembly. The tensioning instrument further defines at least one slotwhich allows movement of a carriage between a non-tightened position anda tightened position, permitting a surgeon to tighten the band. Alongitudinal cylinder of the tightening instrument permits the insertionof various tools, e.g., to restrict movement of the vertebral structurerelative to the implant rod.

An embodiment of a method of implanting a spinal clamp assembly along atleast two vertebrae includes: providing a spinal clamp assemblyincluding a clamp housing, a locking element, a band, and a surgicalrod; positioning the housing along the rod at a desired locationadjacent a vertebra; wrapping a band about a lamina and through thehousing; inserting the locking element within the housing to capture therod; provisionally locking the locking element; engaging a tensioninginstrument with the spinal clamp assembly; inserting the band through acarriage of the tensioning instrument; moving the carriage to atightened position to secure the band; and locking the locking element.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the general inventive concepts will becomeapparent from the following detailed description made with reference tothe accompanying drawings.

FIG. 1 a is a front perspective view of a spinal clamp housing;

FIG. 1 b is a side perspective view of the housing of FIG. 1 a;

FIG. 1 c is a front view of a band wrapped about the housing of FIG. 1a;

FIG. 1 d is a bottom perspective view of the housing of FIG. 1 a;

FIG. 1 e is a front cross-sectional view of a band engaged with thehousing of FIG. 1 d;

FIG. 2 is a front perspective view of a spinal rod positioned within thehousing and band assembly of FIG. 1 c;

FIG. 3 is a front cross-sectional view of a set screw positioned withinthe housing of FIG. 1 a, shown without a rod or band;

FIG. 4 is a top perspective view of a locking element of FIG. 3;

FIG. 5 a is a perspective view of a provisional locking tool engagedwith a rod and spinal clamp assembly, shown without a band;

FIG. 5 b is an enlarged perspective view of the designated circular areaof FIG. 5 a;

FIG. 5 c is a perspective view of the provisional locking tool of FIG. 5a;

FIG. 6 a is a front view of a tensioning instrument;

FIG. 6 b is a rear view of the tensioning instrument of FIG. 6 a;

FIG. 7 a is a front perspective view of the tensioning instrument ofFIG. 6 a, shown engaged with the rod and spinal clamp assembly of FIG. 5a;

FIG. 7 b is an enlarged perspective view of the designated circular areaof FIG. 7 a;

FIG. 7 c is a front cross-sectional view of FIG. 7 a, shown without atightening rod;

FIG. 7 d is an enlarged perspective view of the designated circular areaof FIG. 7 c;

FIG. 7 e is a perspective cross-sectional view of a center portion ofthe tensioning instrument of FIG. 7 a;

FIG. 7 f is an enlarged perspective view of a bearing ring of thetensioning instrument of FIG. 7 a;

FIG. 7 g is a front perspective view of a tightening rod of thetensioning instrument of FIG. 7 a;

FIG. 8 is a perspective view of FIG. 7 a, shown with the band routedthrough a carriage of the tensioning instrument, with the carriage in anon-tightened position;

FIG. 9 a is an enlarged perspective view of the carriage of FIG. 8;

FIG. 9 b is a front cross-sectional view of the carriage of FIG. 9 a;

FIG. 10 a is a perspective view of FIG. 8, shown with the carriage in atightened position;

FIG. 10 b is perspective view of a tightening tool of FIG. 10 a;

FIG. 11 a is a perspective view of FIG. 10 a, shown with the carriage ina tightened position and a screwdriver tool inserted within thetensioning instrument;

FIG. 11 b is an enlarged cross-sectional view of the screwdriver toolengaging the set screw;

FIG. 11 c is a side view of the screwdriver tool of FIG. 11 a;

FIG. 12 is a front perspective view of another spinal clamp housing;

FIG. 13 is a bottom perspective view of the spinal clamp housing of FIG.12;

FIG. 14 is a front sectional view of the spinal housing of FIG. 13, showwith a pin and band installed in the housing;

FIG. 15 is a front view of a tensioning instrument;

FIG. 16 is a front sectional view of the tensioning instrument of FIG.15;

FIG. 17 is front view of a tightening rod of the tensioning instrumentof FIG. 15;

FIG. 18 is a perspective view of a bearing ring of the tensioninginstrument of FIG. 15;

FIG. 19 is a front cross-sectional view of the carriage of FIG. 15;

FIG. 20 is a cross-sectional view of a center portion of the tensioninginstrument of FIG. 15;

FIG. 21 is a cross-sectional view of a center portion of the tensioninginstrument of FIG. 15, shown with the tightening rod installed and thecarriage in a non-tightened position;

FIG. 22 is a cross-sectional view of a top portion of the tensioninginstrument of FIG. 15, shown with the tightening rod installed;

FIG. 23 is a cross-sectional view of a top portion of the tensioninginstrument of FIG. 15, shown with the screwdriver tool installed;

FIG. 24 a is a perspective view of another embodiment of the invention,showing a dual tether band assembly;

FIG. 24 b is a perspective view of the assembly of FIG. 24 a, shown witha part of the dual tether band split into two individual bands;

FIG. 25 is a perspective view of another embodiment of the invention,showing a tether band/pedicle screw assembly;

FIG. 26 is a perspective view of another embodiment of the invention,showing a tether band/cross-connector assembly;

FIG. 27 a is a perspective view of another embodiment of the invention,showing a tether band/hook assembly with the hook and the band in anopposite orientation;

FIG. 27 b is a perspective view of another embodiment of the invention,showing a tether band/hook assembly;

FIG. 28 is a perspective view of another embodiment of the invention,showing a two housing assembly and a transverse tether band;

FIG. 29 is a perspective view of another embodiment of the invention,showing the installation of a tether band/pedicle screw assembly actingas a reduction device;

FIG. 30 is a perspective view of another embodiment of the invention,showing another tether/band/pedicle screw assembly;

FIG. 31 a is a perspective view of another embodiment of the invention,showing a tether band/rod/hook assembly;

FIG. 31 b is a perspective view of another embodiment of the invention,showing another tether band/rod/hook assembly; and

FIG. 32 is a front view of a tether band/pedicle screw assembly as usedin a reduction process.

DETAILED DESCRIPTION

This Detailed Description merely describes exemplary embodiments inaccordance with the general inventive concepts and is not intended tolimit the scope of the invention in any way. Indeed, the invention asdescribed in the specification is broader than and unlimited by theexemplary embodiments set forth herein, and the terms used herein havetheir full ordinary meaning.

The general inventive concepts will now be described with occasionalreference to the exemplary embodiments of the invention. This generalinventive concept may, however, be embodied in different forms andshould not be construed as limited to the embodiments set forth herein.Rather, these embodiments are provided so that this disclosure will bethorough and complete, and will fully convey the scope of the generalinventive concepts to those skilled in the art.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art encompassing the general inventive concepts. The terminology setforth in this detailed description is for describing particularembodiments only and is not intended to be limiting of the generalinventive concepts. As used in this detailed description and theappended claims, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

Unless otherwise indicated, all numbers expressing quantities ofingredients, properties such as molecular weight, reaction conditions,and so forth as used in the specification and claims are to beunderstood as being modified in all instances by the term “about.”Accordingly, unless otherwise indicated, the numerical properties setforth in the specification and claims are approximations that may varydepending on the suitable properties sought to be obtained inembodiments of the present invention. Notwithstanding that the numericalranges and parameters setting forth the broad scope of the generalinventive concepts are approximations, the numerical values set forth inthe specific examples are reported as precisely as possible. Anynumerical values, however, inherently contain certain errors necessarilyresulting from error found in their respective measurements.

The invention is directed a tether clamp and implantation system for usein orthopedic surgery. The system provides a temporary implant intendedto provide temporary stabilization as a bone anchor during thedevelopment of solid bony fusion and aid in the repair of bonefractures. Exemplary indications for use include, but are not limitedto, the following applications:

-   -   1. Spinal trauma surgery, used in sub-laminar, interspinous, or        facet wiring techniques.    -   2. Spinal reconstructive surgery, incorporated into constructs        for the purpose of correction of spinal deformities such as        scoliosis, kyphosis, spondylolisthesis.    -   3. Spinal degenerative surgery, as an adjunct to spinal fusions.    -   4. Treatment of idiopathic and neuromuscular scoliosis in        patients eight years of age and older.        The inventive system may also be used in conjunction with other        medical implants made of metal, for example, titanium alloy or        cobalt chromium alloy, whenever “wiring” may help secure the        attachment of other implants.

An embodiment of the invention which will now be discussed is a spinalclamp implant. The spinal implant is used to aid in fusion andstabilization in one or more vertebrae during a posterior accesssurgery. The spinal clamp can be used with one or more similar spinalclamps to provide anchoring points for a surgical rod. The spinal clampcan further be used with conventional screw and tulip head implants. Forexample, the spinal clamp may be secured to third lumbar vertebra L3,while conventional screw and tulip head implants are secured to thesecond lumbar vertebra L2 and the fourth lumbar vertebra L4. Whendiscussing the spinal clamp and implantation of the spinal clamp, theterms “proximal” and “distal” are used relative to the surgeon, and notthe operating field, i.e., not relative the patient.

An embodiment of this invention was discussed in U.S. Provisional PatentApplication Ser. No. 61/534,453, entitled TETHER CLAMP AND IMPLANTATIONSYSTEM and filed Sep. 14, 2011, the entire disclosure of which isincorporated herein by reference.

Referring now to the drawings, a spinal clamp housing 10 is shown inFIGS. 1 a and 1 b. The housing is adapted for placement at a desiredimplantation point adjacent to a vertebra. The housing 10 may beconstructed of suitable material, such as for example, stainless steel,cobalt chromium, or titanium.

The housing is generally cylindrical shaped and defines a longitudinalaxis L_(A) (best seen in FIG. 3). More specifically, the housingincludes a center recess 12 defined by opposing arms 14, 16 extendingfrom a base 17. An internal surface of the arms 14, 16 include a matingengagement surface, such as for example, a threaded surface 18. Thethreaded surface mates with a locking element, such as for example, aset screw, a blocking nut, or a blocker. An exterior of the exemplaryarms 14,16 include a flat surface 20. A tightening instrument engagesthe flat surface 20 to prevent housing 10 rotation while the set screwis rotated into a locked position. This operation will be discussed infurther detail. It should be apparent to one with skill in the art thatother styles, types, and sizes of surfaces for locking elements andtensioning instrument mating can be used in the practice of thisinvention.

The housing 10 includes structural features to permit a band to bewrapped securely about the housing. A first slot 22 is located at thebottom of the recess 12 and defines a passage for a band along alongitudinal axis of the housing. The first slot may allow use by asurgeon as a starting point for band travel within and in the vicinityof the housing 10. For example, a knot may be tied at the beginning ofthe band to prohibit one end of the band from entering the slot andpassing through to the bottom side of the housing, or one end of theband may include a clip larger in size than the slot 22. A second slot24 and a third slot 26 are formed in opposing positions on either sideof the housing 10. These slots 24, 26 may permit band travelperpendicular to the longitudinal axis of the housing 10. An exemplarytravel path of a band 28 is illustrated in FIG. 1 c. The band 28 isillustrated in an exemplary pattern, for example, routed in a patternaround a lamina (not shown).

The housing 10 further includes apertures 32. These apertures may beused by a surgeon for various purposes, such as for example, graspingthe housing 10 during implantation, or insertion of a pin for astructural anchor for another assembly piece, such as for example, thetether band.

Structural features of the bottom of the spinal clamp housing are bestseen in FIG. 1 d. In this embodiment, the housing 10 a includes twoslots 22 a, 22 b, separated by a bridge 23, at the bottom of the housingrecess. The slots 22 a, 22 b may allow use by a surgeon as a startingpoint for band travel within and in the vicinity of the housing 10 a.For example, a first end of the band 28 may be routed through both slotsas shown in FIG. 1 e, and secured to a distal location 29 of the band,to secure the band to the housing 10 a. In the exemplary embodiment, theband is integral to the housing and secured prior to surgery, forexample, during surgery preparation or by a manufacturer. In otherembodiments, the surgeon may attach the first end of the band at thedistal location 29 by one of several methods, including sewing the firstend to the band. It should be understood by those with ordinary skill inthe art that the number of slots used to secure the band, if any, aswell as the shape and location of the slots, may vary in the practice ofthis invention.

Another embodiment of the invention includes a housing having differentstructural features. Specifically, the housing 210 illustrated in FIGS.12-14 includes a single aperture 122 at the bottom of housing. Theaperture as shown is a rectangular shaped slot. It may be of anysuitable shape, width and length. As shown, the single slot 122 is widerthan the double slots 22 a, 22 b shown in the housing 10 of FIG. 1 d.

The base of the housing 210 is absent any apertures orientedperpendicular to a position of an installed surgical rod. The housing210 does include two holes 132 for supporting a pin 123 as seen in FIG.14. The holes are positioned co-axial with an installed position of asurgical rod. The end of the band is fixed to provide a loop forslipping over the pin, or the band may be fixed to the pin. As shown, aloop and the end of a tether band 128 is formed by fixing two bandlengths 130 a, 130 b.

Referring now to FIG. 2, a surgical rod 34 placed within the recess 12of the housing is shown. The housing is concave-shaped to accept andlaterally retain the rod 34 within the arms 14, 16. The weight of therod 34 applies a force to pinch a portion of the band 28 against thehousing 10.

During implantation, the next step is to provisionally lock the rod inplace with use of a set screw. A set screw 36 is shown engaged with ahousing 10 in FIG. 3. The rod 34 and band 28 are not shown for clarity.As shown in FIGS. 3 and 4, the set screw 36 has a threaded externalcircumferential surface 38 which engages the internal threaded surface18 of the arms 14, 16. A top surface 40 of the set screw 36 includes acut-out recess 42. The recess 42 is shaped to accept locking tools.

FIGS. 5 a and 5 b illustrate a provisional locking tool 50 engaged witha set screw 36. In the implantation of the spinal clamp, a surgeon usesthe provisional locking tool 50 to tighten the set screw enough totemporarily contain the rod 34. The set screw must not be locked inplace until the band is sufficiently tightened about the target lamina.In a further surgical step, the set screw 36 is locked in a finalposition.

As shown in FIG. 5 c, the provisional locking tool 50 includes aninstrument rod 52 and palm handle 54. The palm handle 54 may beseparable from the instrument rod 52. The system may include multipletools, each with specifically shaped instrument rods. For example, theinstrument rod 52 includes a constant diameter shaft terminating in asocket head 56 sized to mate with the recess 42 of the set screw 36.

The spinal clamp installation system includes a tensioning instrumentfor use by a surgeon to tighten a band and securing the vertebralstructure relative to the implant rod. The installation system isarranged for user ease of installation. As shown in the Figures, e.g.,FIGS. 3 and 7 d, the housing 10, set screw 36 and tensioning instrument60 are all positionable about a common longitudinal axis L_(A). Anytools used in the installation, either prior to the engagement of thetensioning instrument, or inserted within the internal channel of thetensioning instrument from a proximal end to a distal end, are alsopositioned along the same common axis. This arrangement also promotesincreased user flexibility, e.g., the user may easily incrementallytighten a band of a spinal clamp assembly, then by retract a tool fromthe set screw and then disengaging the tensioning instrument from thehousing, move to the next sequential spinal clamp assembly along thesurgical rod, and make a similar incremental adjustment.

FIGS. 6 a and 6 b illustrate front and rear views of a tensioninginstrument 60. The instrument includes an elongated cylinder 62. Thecylinder permits the insertion of tools from a proximal end 64 to adistal end 65 to manipulate the set screw 36, and further contains ahollow tightening rod 66. The tightening rod 66 is used by the surgeonto secure the band 28 in a final position.

The cylinder 62 is adapted for securing the spinal clamp in a finalposition relative the target vertebra. FIGS. 7 a-7 d illustrate variousviews of the tensioning instrument 60 engaged with a spinal rod. Thecylinder 62 includes projections 68 at the distal end 65. An archedsection 63 a between two adjacent projections engage a top surface ofthe rod 34 (see FIG. 7 b). A flat portion 63 b between other adjacentprojections engage the flat portions 20 on the exterior of the housing10, to prohibit movement of the housing. The cylinder further definestwo opposing slots 70, 72. The slots permit travel of a carriage 74within the slot, at least partially between a distal end 70 a (see FIG.7 a) and proximal end 70 b (see FIG. 10 a). Two protruding tabs 76, 78ride within the slots during movement of the carriage. The mechanics ofthis movement will be discussed in further detail.

The tensioning instrument is structured to tighten the band 28 to securethe housing 10 to the rod 34. As best seen in FIG. 7 e, the cylinder 62includes an interior surface 80 defining a hollow chamber. Within theproximal portion of the chamber, the tightening rod 66 mates withinternal threads of the cylinder. The tightening rod 66 is illustratedin FIG. 7 g and includes a knob 82, threaded portion 84, and a distal,non-threaded portion 86. The distal position 86 includes holes 88 forengagement by set screws (not shown) which secure a retaining ring 90(see FIG. 7 e). The retaining ring 90 moves axially within the cylinderas the tightening rod 66 is manipulated by the surgeon.

A bearing ring 92 is disposed to the proximal side of the retaining ring90, as best shown in FIG. 7 e. Further as shown in FIG. 7 f, the twotabs 76, 78 radially protrude from opposing sides of the bearing ring92. A center aperture 94 permits passing of the distal portion 86 of thetightening rod 66. A top surface 96 of the bearing ring 92 may engage ashoulder 98 of the tightening rod to limit entry of the rod into thecylinder in a distal direction.

The bearing ring 92 is adapted for connection to the carriage 74. Asshown in FIG. 7 e, a wing 98 extends radially from a base of the bearingring into the carriage 74, which is constructed from two pieces 74 a, 74b (see FIG. 9 a). The carriage may be constructed of a suitablematerial, such as for example, plastic or metal, and include twosnap-fit pieces that enclose the wing 98. A carriage half 74 a isillustrated in FIG. 7 e and includes a spur 100 which is biased in adirection toward the cylinder 62 by a torsion spring 102. The spur 100is operated by a handle 103 (see FIG. 9 a) to permit threading of theband 28 in a proximal direction through a channel 104 in the carriage74. Teeth on the spur 100 prohibit return movement of the band in thedistal direction.

FIG. 8 shows the band 28 inserted through the carriage 74 and properlypositioned for use of the tensioning instrument. The carriage is in anon-tightened position in FIG. 8. Front perspective and cross-sectionalviews of the carriage 74 are shown in FIGS. 9 a and 9 b, respectively,with the band 28 in an inserted position. As shown in FIG. 9 b, teeth onthe spur 100 press the band 28 against the wall of the channel 104.

As previously discussed, a surgeon may secure the housing 10 in placerelative to the targeted vertebra by manipulation of the tightening rod66. Referring now to FIG. 10 a, a tightening tool 110 is shown engagedwith the knob 82 of the tightening rod 66. As shown, the rod 66 has beenturned and axially moved in a proximal direction away from the housing10. As such, the carriage has moved axially along the exterior of thecylinder 62, and within the range between the slot 70 distal end 70 aand proximal end 70 b, at the discretion of the surgeon. As the carriagemoves proximally, the band 28 is tensioned in a proximal directionsecuring the vertebral structure relative to the implant rod. Thecarriage is in a tightened position in FIG. 10 a.

FIG. 10 b is perspective view of the tightening tool 110 of FIG. 10 a.The tightening tool includes a palm handle 54 and an instrument shaft112, which terminates at a head 114 for engaging a recess in the knob82. As previously discussed in regard to other tools, the palm handle 54may separate from the instrument shaft 112 so that a single handle canaccommodate multiple shafts for multiple purposes during implantation.

After the band 28 is sufficiently tensioned, the surgeon may lock theset screw 36 into a desired and final position. FIGS. 11 a-11 c detailaspects of this locking process. In FIG. 11 a, a perspective view ofFIG. 10 a is shown with the carriage in a tightened position, thetightening tool 110 removed, and a screwdriver tool 120 inserted withinthe tensioning instrument 60. An enlarged cross-sectional view of thehead 56 of the screwdriver tool 120 engaged with the set screw 36 isshown in FIG. 11 b. In this position, the surgeon may tighten the setscrew as desired by turning the tool 120.

FIG. 11 c is perspective view of the screwdriver tool 120. The toolincludes a palm handle 54 and an instrument shaft 122, which terminatesat a head 56 for engaging the recess 42 in the set screw. As previouslydiscussed in regard to other tools, the palm handle may separate fromthe instrument shaft. The exemplary shaft 122 shown includes a shoulder124 to accommodate the internal dimensions of the cylinder 62 andtightening rod 66.

Another embodiment on the tensioning instrument will now be discussed.The tensioning instrument 160 and related parts are illustrated in FIGS.15-23. The tensioning instrument 160 has similar features as thediscussed embodiment of FIGS. 5 a-11 b. However, the tensioninginstrument 160 includes structural differences of certain componentsrelated to tensioning. The embodiment discussed is exemplary only, andother structural difference of the same or different components can beutilized in the practice of the invention.

FIGS. 15 and 16 illustrate front and sectional views, respectively, of atensioning instrument. The tensioning rod 166 is fixed by one or morepins and moves only axially upon rotation. In other words, thetensioning rod does not translate along the longitudinal axis of thetensioning instrument. As seen in FIGS. 16, 17 and 18, the inside of thebearing ring is threaded, and no retaining ring or set screws areincluded in the assembly as in other embodiments. The cross-sectionalview of FIG. 21 shows detail of the tensioning rod, bearing ring andcarriage assembly.

Referring specifically now to FIG. 15, a front view of a tensioninginstrument 160 is illustrated. The tensioning instrument includes ahollow cylinder 162. As best shown in the sectional view of FIG. 16, thecylinder has a smooth internal surface 162 without female threads. Withthe internal surface being smooth, the threaded portion 184 of thetightening rod 166 does not engage the inside surface of the hollowcylinder 162. As shown in FIGS. 16-18 and 21, the tightening rod 166engages a bearing ring 192. Specifically, a threaded surface 184 of thetightening rod engages an inside threaded surface 195 of the bearingring 192.

The bearing ring 192 is adapted for connection to the carriage 174. Asshown in FIG. 18, a wing 198 extends radially from a base of the bearingring. The wing extends into the carriage 174 as in a previouslydiscussed embodiment. Two tabs 176, 178 are oval in shape and ride witha slot 170 on either side of the tensioning instrument 160 as thecarriage travels from a lower non-tensioned position to a highertensioned position, as previously discussed.

The carriage advantageously “auto-locks” in operation, prohibitingdisengagement of the band in the distal direction, but allowing for easyslack removal by pulling in the proximal direction.

174 illustrated in FIGS. 16 and 19 includes a lever 200 which is biasedin a direction toward the cylinder 162 by a torsion spring 202. Thelever 200 is operated by a handle 199 to permit threading of a tetherband in a proximal direction through a channel 204 in the carriage 174.Teeth 200 on the lever 197 prohibit return movement of the band in thedistal direction.

The invention can be utilized in various applications and techniques.Several other embodiments of the invention and methods of use asillustrated in FIGS. 24 a-32. A dual housing assembly is illustrated inFIGS. 24 a-24 b. The figures illustrate two housings 210 a, 210 b with adual tether band 300 fixed to the bottom of each housing. The strandsare connected to the housing as by the arrangement shown in FIG. 14,with the individual strands 302 a, 302 b of the band connected to a pininserted through the housing. The proximal end of the band can be splitin two ends 304 a, 304 b after being passed through as lot on anotherhousing, or other device. After splitting and passing, each end 304 a,304 b is secured independent of the other to each housing 210 a, 210 b,such as for example, under a surgical rod.

Other embodiments of the invention can include housings having pediclescrew capability, such as for example, the housing illustrated in FIG.25. The housing 310 includes a screw portion 314 having constructionsuitable for use as a pedicle screw. One or more slots allow foranchoring or passing of a tether band. As shown, a distal loop of a band312 surrounds a mounting pin 320 and exits a lower slot 316 b, and uponre-entry to the housing 310 passes through an upper slot 316 a and overa surgical rod 318. This arrangement allows for additional fixationoptions, such as for example, to support resistance to screw pullout,e.g., in osteopenic bone. A similar arrangement is shown in FIG. 26, inwhich a band surrounds a second surgical rod 320. In this embodiment,the band is mounted to a pin 320 and exits out an upper slot. In thisarrangement with two surgical rods 318, 320, the assembly is used as across connector to add bi-lateral stability in rod/implant constructs.

Other embodiments of the invention can include housings with laminarhooks used to engage bone. Specifically, the housing along thecombination of hook, rods and tethers to prevent dislodging of hook, forexample, to prevent proximal junctional kyphosis. FIGS. 27 a and 27 billustrate housing 330, 338 with hooks 336, 340, respectively. In FIG.27A, the rod 332 and tether 334 are positioned at opposing orientations,and with the tether above the rod. In contrast, the housing 338 of FIG.27 b positions the rod above the tether and at the same orientation,i.e., in a co-axial position. Other combinations of rod and tetherpositions can be practiced with this invention.

Another exemplary assembly is shown in FIG. 28. As shown, a pediclescrew housing 344 is implanted into a vertebrae 348. A second housing isfixed to a rod 346 and positioned on a opposite side of the vertebrae348 relative the pedicle screw housing 344. A tether 350 stretches froma pin mounting in the housing 342, through a surgical created slot inthe vertebrae, and to the pedicle screw housing 344. The use of tetherband 350 in a transverse arrangement helps derotation of vertebral bodyand prohibits any creep of construct.

Multiple inventive housings and a tether band can also be advantageouslyused during surgery to help implant a rod. For example, FIG. 29illustrates an exemplary use of a first housing, a pedicle screwhousing, and a tether 366 in which the tether band is used to laterallytranslate the pedicle screw housing to the implant rod. After the firsthousing 360 is mounted to a rod 368, the pedicle screw housing 362 a (asshown in a first position) is translated to a second position 362 b byuse of the tether, in effect moving the vertebrae (from a first position364 a to a second position 364 b) to an position engageable with the rod368.

As discussed, the inventive housing include slots suitable for passingof a tether. For example, pedicle screws with slots for tether band maybe used to allow additional fixation options by accommodating passage ofa tether band thru the head of the screw. As shown in FIG. 30, a pediclescrew housing 370 includes a screw portion 372, and a head 382 having aslot 374 in each arm. A tether 376 may pass above or below a surgicalrod 378, and may be held in place by a set screw 380. Other examplesusing hooks 392 are illustrated in FIGS. 31 a and 31 b. These housings394, 390 allow for additional fixation options by accommodating passageof a tether band 376 through the body of the housing transversely (asshown in FIG. 31 a) or along the axis of the rod 378 (as shown in FIG.31 b). Other orientation combinations are possible in practice ofinvention.

Referring now to FIG. 32, a tether band and pedicle screw housing isshown in use in a reduction process. Specifically, a tether 408 is usedas a reduction device to seat a rod 404 into a pedicle screw housing402. As shown, the housing is implanted into a vertebrae 400. By use oftensioning instrument 406, the vertebrae 400 and housing 402 is moved ina direction A₂ to seat the rod in a desired position.

While various inventive aspects, concepts and features of the generalinventive concepts are described and illustrated herein in the contextof various exemplary embodiments, these various aspects, concepts andfeatures may be used in many alternative embodiments, eitherindividually or in various combinations and sub-combinations thereof.Unless expressly excluded herein all such combinations andsub-combinations are intended to be within the scope of the generalinventive concepts. Still further, while various alternative embodimentsas to the various aspects, concepts and features of the inventions (suchas alternative materials, structures, configurations, methods, circuits,devices and components, software, hardware, control logic, alternativesas to form, fit and function, and so on) may be described herein, suchdescriptions are not intended to be a complete or exhaustive list ofavailable alternative embodiments, whether presently known or laterdeveloped. Those skilled in the art may readily adopt one or more of theinventive aspects, concepts or features into additional embodiments anduses within the scope of the general inventive concepts even if suchembodiments are not expressly disclosed herein. Additionally, eventhough some features, concepts or aspects of the inventions may bedescribed herein as being a preferred arrangement or method, suchdescription is not intended to suggest that such feature is required ornecessary unless expressly so stated. Still further, exemplary orrepresentative values and ranges may be included to assist inunderstanding the present disclosure; however, such values and rangesare not to be construed in a limiting sense and are intended to becritical values or ranges only if so expressly stated. Moreover, whilevarious aspects, features and concepts may be expressly identifiedherein as being inventive or forming part of an invention, suchidentification is not intended to be exclusive, but rather there may beinventive aspects, concepts and features that are fully described hereinwithout being expressly identified as such or as part of a specificinvention. Descriptions of exemplary methods or processes are notlimited to inclusion of all steps as being required in all cases, nor isthe order that the steps are presented to be construed as required ornecessary unless expressly so stated.

1. A clamp assembly for providing stabilization as a bone anchor, theassembly comprising: a housing defining a longitudinal axis, a recess,and at least one first slot disposed at the bottom surface of thehousing, the housing having two opposing arms extending from a base; alocking element positionable within the recess in a co-axialrelationship to a mating surface on the housing, and a band sized fortravel along a predetermined path defined in part by the at least onefirst slot in the housing and at least one other slot in the housing. 2.The assembly of claim 1 wherein the housing includes a second slotformed in one extending arm and a third slot formed in an opposingposition in the other extending arm.
 3. (canceled)
 4. The assembly ofclaim 2 wherein at least two first slots are disposed at the bottom ofthe recess.
 5. The assembly of claim 2 wherein the second slot and thethird slot define a portion of the predetermined path of the band. 6.The assembly of claim 1 wherein the housing is adapted to receive asurgical rod within the recess and between the two opposing arms.
 7. Theassembly of claim 1 wherein the housing is cylindrical-shaped.
 8. Theassembly of claim 1 wherein the housing is a uniform piece absent anymoving portions.
 9. The assembly of claim 1 wherein at least a portionof an outside surface of each arm is planar.
 10. A clamp systemcomprising: a spinal clamp assembly comprising: a housing defining alongitudinal axis, a recess, and at least one slot, the housing havingtwo opposing arms extending from a base; a locking element having atool-engaging surface, and positionable within the recess in a co-axialrelationship to the housing; and a band sized for travel along apredetermined path defined in part by the at least one slot in thehousing and at least one other slot in the housing; and a tensioninginstrument having a hollow body, a proximal end, a distal end, theproximal end sized for insertion of a tool into a length of theinstrument and the distal end engageable with the housing in a co-axialrelationship, and a carriage having a band securing mechanism; whereinthe tensioning instrument defines at least one travel slot which permitsmovement of the carriage between a band non-tightened position and aband tightened position.
 11. The system of claim 10 comprising atightening rod sized for insertion into the proximal end of thetensioning instrument and engageable with the carriage, wherein an axialposition of the carriage is controllable by user manipulation of thetightening rod.
 12. The system of claim 10 wherein the distal end of thetensioning instrument is slideable over the outside surfaces of the twoopposing arms.
 13. The system of claim 10 comprising a locking toolsized for insertion through the tensioning instrument from the proximalend to the distal end and engageable with the tool-engaging surface ofthe locking element.
 14. The system of claim 11 comprising a tensioningtool sized for manipulation of the tightening rod when the housing,locking element, tensioning instrument, and tensioning rod arepositioned along a common longitudinal axis. 15-20. (canceled)
 21. Theassembly of claim 1 wherein the housing includes at least one apertureadapted for inserting a pin.
 22. The assembly of claim 21 wherein thebase includes at least two apertures, with at least one aperture oneither side of a slot disposed at a bottom of the recess.
 23. Theassembly of claim 21 wherein at least one of the two arms includes atleast two apertures, with at least one aperture on either side of a slotdisposed in the arm.
 24. The assembly of claim 1 wherein a hook extendsfrom the bottom of the base.
 25. The assembly of claim 1 wherein a screwextends from the bottom of the base.
 26. (canceled)
 27. (canceled) 28.The assembly of claim 1 wherein the locking element is a set screw. 29.The assembly of claim 9 wherein the planar portions of the outsidesurfaces of the two opposing arms are parallel.
 30. The assembly ofclaim 1 wherein at least a portion of the inside surface of each arm isthreaded.
 31. The assembly of claim 2 wherein the at least one firstslot, the second slot, and the third slot are arranged such as to definea portion of the predetermined path of the band, the path originating atthe at least one first slot, leading outside of the housing, andsubsequently back through the housing.
 32. The assembly of claim 31wherein the path of the band back through the housing is above the baseand below the locking element.